How big/expensive a job is injection damp-proofing?

Joined
17 May 2013
Messages
1,339
Reaction score
24
Country
United Kingdom
I mean where they inject along the brick-work ever 6-12" to block rising damp.

We have this along the long north wall of our house apart from at one end, which is exactly where we have some damp inside - coincidence?!
The only other evidence of rising damp is on a converted green-house, now a garden room at one end. About 12'.

Is having this done quite quick and painless or is it a big, expensive job? Our house is made of Victorian brick?
Do we need a specialist renovation company or is it something a builder can do if they have the right tool?
 
Joined
9 Feb 2010
Messages
1,560
Reaction score
275
Location
Leicestershire
Country
United Kingdom
You can hire the injection equipment and do it yourself if you want to. One thing to note is that if your wall plaster has signs of dampness you are best to replaster the affected area and some margin beyond using a suitable undercoat. There are various suitable undercoats but the lightweight gypsum plasters are not. You can only use the gypsom plaster as a skim coat.

You need to deal with all the bricks across at your "DPC" level including the ones behind where the wall thickness hides bricks in the middle. Often easy to drill from the other side if you have access.
 
Sponsored Links
Joined
17 May 2013
Messages
1,339
Reaction score
24
Country
United Kingdom
Makes sense - plaster attracts water and once it's damp may be ruined anyway right?
And if you've already got damp, it will take some time to dry out - is it worth waiting before re-plastering or is the point you apply a damp-proof solution (like you might use when tanking) so you can decorate on top right away?

How long would it take for a wall to dry out?
 
Joined
9 Feb 2010
Messages
1,560
Reaction score
275
Location
Leicestershire
Country
United Kingdom
Damp plaster is not really the problem, it is the salts that get left behind when the moisture evaporates. Those salts actually encourage dampness and that is the reason to replace it. Perished plaster of course needs replacing.
Unless the wall is actually wet you can plaster pretty much straight away. There is loads more water in the new plaster anyway. There is not usually any need to apply further treatment to the wall in addition to the injected chemicals. Tanking below ground levels if applicable is a different issue.

As for time to dry out there is no set time as it really depends on how wet the wall is to start with. For the area replastered some consider leaving to dry for six months as this includes time for the bricks to dry out to. In practice you may find a few weeks will be OK. The main thing being the plaster needs to be bone dry.

Edit:
Regards the salts - they are present in the earth and so the problem with them relates to rising damp. A wall damp from a leaking pipe can dry out and be fine unless it has been going on too long and the plaster is perished or otherwise damaged.
 
Last edited:
Sponsored Links
Top